Honokiol and magnolol (an isomer of honokiol) are small-molecule polyphenols isolated
from the barks of Magnolia officinalis, which have been widely used in traditional Chinese and
Japanese medicines. In the last decade, a variety of biological properties of honokiol and magnolol
(e.g., anti-oxidativity, antitumor activity, anti-depressant activity, anti-inflammatory activity,
neuroprotective activity, anti-diabetic activity, antiviral activity, and antimicrobial activity) have been
reported. Meanwhile, certain mechanisms of action of some biological activities were also
investigated. Moreover, many analogs of honokiol and magnolol were prepared by structural
modification or total synthesis, and some exhibited very potent pharmacological activities with improved water solubility.
Therefore, the present review will provide a systematic coverage on recent developments of honokiol and magnolol
derivatives in regard to semisynthesis, total synthesis, and structure-activity relationships from 2000 up to now.